When navigating to edit a recurring event in a calendar list, the end user will be greeted withthis error:
"Unable to get attachments for list item"
Disabling attachments alleviates the issue however, a fix was rolled into K2 Five Fixpack 18.
The other issue addressed with FP18 is when editing a single event the edit is applied to the entire series.
Symptoms include "Unable to get attachments for list item" appearing when drilling into an event as well as edits on a single event being applied to all instances.
These issues were addressed in Fix Pack 18.